<!DOCTYPE html>
<html>
<head>
    <meta charset='UTF-8'>
    <title>定位-relative</title>
    <style>
        body{
            /*background: green;*/
            color: white;
            padding: 10px;
        }
        div {
            background: deeppink;
            padding: 20px;
        }
        div.re{
            background: dodgerblue;
            position: relative;
            top: 10px;
            left: 10px;
            opacity: 0.8;
        }
    </style>
</head>
<body>
    <div>
        i am normal
    </div>
    <div class="re">
        i am relative
    </div>
    <div>
        i am normal
    </div>
</body>